Traditionally in the sign industry, a frequently desired "halo" effect is achieved with the use of high voltage neon, incandescence or fluorescence type devices. These are located behind signs that are spaced from a wall so that the back illumination from these conventional light sources creates the so-called "halo" effect. These light sources require that the sign be at least sufficiently large in area so as to enable these light sources to hide behind the back of the sign. These traditional approaches in the sign industry are limited to letters large in size depth and stroke width. These constraints are both physical and building code imposed. As a result the back illumination of small signs or of signs whose cross-dimension is small cannot be accommodated with these conventional devices.
In a known technique using conventional fibers are provided to back illuminate signs. The light source and fibers are obtained from a well known supplier such as Supervision International of Orlando Fla. The light fibers are applied through holes in the wall to which the sign is to be attached and terminate in a cantilever fashion from the wall to illuminate the back of the sign. Light from these fibers is then reflected from the back of the sign towards the wall to provide the desired back illumination or halo effect. A problem with such back lighting is caused by the myriad holes that need to be made in the wall to accommodate the fibers as well as a reduced light intensity from the "halo".
In U.S. Pat. No. 5,231,689 light fibers are used to provide direct illumination of signs such as an EXIT sign. As illustrated in FIG. 5 of the '689 patent the fibers are recessed in a substrate material and then covered by a translucent layer containing glass beads. The translucent layer serves to disperse the light from the fibers. This approach does not lend itself to achieve back illumination with a halo effect for signs.